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By Bill Campbell

Workplace safety is often perceived as wearing hard hats, ear plugs and safety vests, but operating an aggregate facility with low-maintenance machines and good preventative maintenance programs can yield significant safety improvements.26 AggregateConveyor 400

Maintenance programs are often overlooked as a safety issue, but every breakdown or repair operation is an opportunity for an accident. Proactive maintenance programs minimize breakdowns and reduce the risk for accidents.

Maintenance operations can be a high risk for accidents, especially when they are unexpected breakdowns. There are physical hazards, electrical hazards, and many other potential accidents.

Maintenance workers encounter potential hazards every time they work on a machine. By selecting machines with higher duty ratings, and replacement parts that have longer life, the number of repair operations are less and there are fewer opportunities for an accident.


Standardization of machines at a large aggregate plant in southern California resulted in increased safety and decreased inventory and maintenance costs. By standardizing the gearbox drives for all the conveyors in this plant, they reduced the number of gear drives from 10 different sizes to four.

The goal was to reduce the number of units required for backup inventory, thus reducing warehousing, parts and overhead costs.

The standardization plan resulted in 70 percent of the applications being designed with a gearbox that is over capacity. The increased cost for oversized gear units is offset by the reduced inventory requirements.

An unforeseen safety advantage resulted because these larger units have a much longer life at this duty rating and are less prone to breakdown, which has resulted in fewer equipment failures and less opportunities for a work-related accident.

Accounting departments are typically concerned about the cost of any standardization plan and need to see a measurable return on investment. In most cases, a step up to the next bigger size will cost 12 to 15 percent more up front. Inventory carrying costs can reduce that by 50 percent if only half the number of spare parts are required.

It’s important to consider that at $7,000 per hour for lost productivity with machine downtime, a single unplanned repair event can exceed the upfront cost of the standardization. And, this doesn’t even factor in the cost of safety.

Other Systems

By extending this plan to other systems that keep an aggregate plant running, bearings can become a good candidate for lowering costs as well as increasing safety via standardization.

Every conveyor pulley is supported by a couple of bearings. From an engineering selection process, a large number of these bearings would be simple ball bearings. By selecting a higher quality spherical roller bearing the expected life of the unit is multiplied many times, resulting in less maintenance repairs and therefore less opportunities for an accident.

Standardizing operations with oversize capacity on select components can provide surprising cost reductions with increased safety as an added bonus. Smaller inventories with broader applications can minimize or eliminate emergency phone calls, overnight air freight bills, lost production and panic. This rule can also be applied to motor size, pump size, shaft size, conveyor belt top cover thickness, and many other wear items.

A Step Further

Taking aggregate safety a step further, you can consider adding accessory equipment to help minimize or prevent maintenance repairs (and potential accidents).

For example, a good skirt board system can be added; one that is designed to seal the conveyor to prevent material leaks. Material leaks mean material clean up. Material clean-ups mean employees with a shovel, or employees with a Bobcat.

Either one of these combinations is a potential opportunity for an accident. There is a skirt board system available today that is adjustable without stopping the system, using only a rubber mallet. No wrenches, no toggle clamps, no torn knuckles and no accidents.

Designing your aggregate plant for worker safety can have the added benefit of providing a cost-effective way to minimize equipment downtime and increase profitability. Planning for standardization with select components can produce a significant return on investment.

Be alert, for safety and profits, in managing your aggregate operations.

Bill Campbell is an aggregate industry specialist with Applied Industrial Technologies. He has a BS in mechanical engineering and a post-graduate diploma in management studies from Glasgow College of Technology.